To in particular secure a movable object against theft, the object may, for example, be connected to another, unmovable object. Two-wheelers are thus, for instance, expediently connected, for example by a two-wheeler lock, to an unmovable object such as a bike stand or a lamppost for securing against theft, provided that the two-wheeler lock is configured therefor and that a suitable unmovable object is present. Otherwise, there still remains the possibility of locking up the movable object in itself such that an unauthorized moving away of the object is at least made more difficult and/or such that the object is not usable in the locked up state. A wheel of a two-wheeler to be secured may, for example, be blocked by a two-wheeler lock such that the two-wheeler either may not be used for riding or may not simply be pushed away. Some two-wheeler locks may, in particular when they form a sufficiently large loop in the closed state, be used both for connection and for the described locking up, while frame locks or spoke locks, for example, are configured especially for a locking up in the sense of an inner blocking.
The security of a respective securing device by which a movable object should be secured against being moved away depends on how easily and thus how fast the securing device may be overcome. In principle, any securing device at the latest be overcome by its destruction when someone has uninterrupted access to the securing device for a sufficiently long time for this purpose. It therefore adds to the security of a movable object protected by a securing device when precautions are taken so that breaking open attempts do not remain unnoticed, but are rather in particular signalized by transmission of an alarm.
For this purpose, for instance a two-wheeler lock may have an alarm function, in addition to the function of preventing a moving away of the two-wheeler, so that it represents a mobile alarm apparatus in this respect. A separate mobile alarm apparatus may, however, also be provided that may generally be releasably fastened to the movable object independently of mechanical securing device for connecting or locking up the movable object. Since attention may already be drawn to an attempted theft and the thief may be disturbed by the simple transmission of an alarm signal, the attachment of such a mobile alarm apparatus may be sufficient to prevent an unauthorized moving away of the movable object with a certain reliability. Provided that the mobile alarm apparatus is, however, not anyway integrated in mechanical securing device such as a two-wheeler lock, it is used in addition to such securing device.
In general, a mobile alarm apparatus may be used for securing the most varied objects and is in particular expedient when the object to be secured is a valuable that is typically easily accessible, at least at times, and is transportable. For example, tools or machines that are used on construction sites and are not locked away as a rule may have to be secured overnight. A mobile alarm apparatus may also be used in order, for instance, to secure a toolbox or another container in which the objects actually to be secured are received, e.g. a shed or a locker.
To be able to respond to an unauthorized access to the secured object, the mobile alarm apparatus must be configured to recognize whether an attempt is made to move the movable object away, in particular whether an attempt is made to break open existing securing device. The most general criterion for the presence of such an attempt comprises mechanical influences taking place on the alarm apparatus. In general, any influence by which the position of the alarm apparatus is changed may be an indication of a break-open attempt. While such mechanical influences may be recognized comparatively simply, this does not in contrast apply to the respective cause of the mechanical influences. This has the result that mechanical influences that have a different cause than a break-open attempt also result in an alarm. For example, a movement of the alarm apparatus that may be caused by a strong wind may already not be distinguished from a break-open attempt. In addition, the movable object to be secured may, for instance, also experience a vibration without a break-open attempt having to be present, for instance when someone accidentally brushes against a connected two-wheeler or moves it slightly in order e.g. to connect a further two-wheeler next to it.
The fact that actual break-open attempts are difficult to distinguish from random or harmless influences results in a high probability of false alarms. Since the alarm signal transmitted to signalize a break-open attempt and to disturb the thief is expediently very loud and thus may also be unpleasant depending on the proximity to the alarm apparatus, such false alarms must be avoided as much as possible. When false alarms occur too frequently, this may have the consequence that the alarm apparatus is no longer used at all, whereby the securing of the movable object actually to be achieved is made worse.